<?php
/**
 * Created by PhpStorm.
 * User: crose
 * Date: 4/17/17
 * Time: 10:17 PM
 */

namespace qfq;

require_once(__DIR__ . '/../store/Config.php');
require_once(__DIR__ . '/../Constants.php');
require_once(__DIR__ . '/../helper/KeyValueStringParser.php');


class Html2Pdf {

    /**
     * @var array
     */
    private $config = array();

    /**
     * Read QFQ config. Only SYSTEM_BASE_URL_PRINT and SYSTEM_WKHTMLTOPDF will be used.
     * Check and get all clean _GET Parameter. Build a URL based on SYSTEM_BASE_URL_PRINT and the delivered URL params.
     *
     * @param array $config
     * @throws UserFormException
     * @throws \exception
     */
    public function __construct(array $config = array()) {

        if (count($config) == 0) {
            $cfg = new Config();

            $config = $cfg->readConfig('');
        }

        $this->config = $config;

        if (!isset($config[SYSTEM_BASE_URL_PRINT]) || $config[SYSTEM_BASE_URL_PRINT] == '') {
            throw new \exception(CONFIG_INI . ' - Missing ' . SYSTEM_BASE_URL_PRINT);
        }

        if (!isset($config[SYSTEM_WKHTMLTOPDF]) || $config[SYSTEM_WKHTMLTOPDF] == '') {
            throw new \exception(CONFIG_INI . ' - Missing ' . SYSTEM_WKHTMLTOPDF);
        }

        if (!is_executable($config[SYSTEM_WKHTMLTOPDF])) {
            throw new \exception(CONFIG_INI . ' - ' . SYSTEM_WKHTMLTOPDF . '=' . $config[SYSTEM_WKHTMLTOPDF] . ' - not found or not executable.');
        }
    }

    /**
     * Return an array with GET params who are clean - they do not violate $pattern.
     *
     * @return array
     */
    private function readCleanGetParam(array $get) {

        $param = array();
        $pattern = '^[\-_\.,;:\/a-zA-Z0-9]*$'; // ':alnum:' does not work here in FF

        foreach ($get as $key => $value) {
            if (preg_match("/$pattern/", $value) === 1) {
                $param[$key] = $value;
            }
        }

        return $param;
    }

    /**
     * Set HTML Header to initiate PDF download.
     *
     * @param $filename
     */
    private function setHeader($filename) {

        header("Content-Disposition: inline; filename=\"$filename\"");
        header("Content-Type: application/pdf");
        header("Content-Transfer-Encoding: binary");
    }

    /**
     * @return string
     * @throws \exception
     */
    public function page2pdf(array $get) {

        if (!isset($get[HTML2PDF_PAGEID]) || $get[HTML2PDF_PAGEID] == '') {
            throw new \exception("Missing GET Parameter '" . HTML2PDF_PAGEID . "'.");
        }

        $urlPrint = escapeshellarg($this->config[SYSTEM_BASE_URL_PRINT] . '/?' . KeyValueStringParser::unparse($get, '=', '&'));
        $wkhtml = $this->config[SYSTEM_WKHTMLTOPDF];

        $rc = 0;
        $filename = tempnam(sys_get_temp_dir(), DOWNLOAD_FILE_PREFIX);
        $filenameEscape = escapeshellarg($filename);

//        $cmd = $wkhtml . " '" . $urlPrint . "' " . $filename . " > $filename.log 2>&1";
//        $cmd = "$wkhtml '$urlPrint' $filename > $filename.log 2>&1";
        $cmd = "$wkhtml $urlPrint $filenameEscape";

        $line = system($cmd, $rc);

        if ($rc != 0) {
            throw new \exception("Error [RC=$rc] $line: $cmd");
        }

        return $filename;
    }

    /**
     * @throws \exception
     */
    public function outputHtml2Pdf() {

        $get = $this->readCleanGetParam($_GET);
        $pageId = Support::setIfNotSet($get, HTML2PDF_PAGEID, 0);

        $filename = $this->page2pdf($get);

        $this->setHeader('print.' . $pageId . '.pdf');
        @readfile($filename);
        @unlink($filename);
//        @unlink($filename . '.log');

        exit; // Do an extremely hard exit here to make sure there are no more additional bytes sent (makes the delivered PDF unusable).

    }

}